1. Field of the Invention
The present invention relates generally to instruments for laparoscopic surgery. In particular, it relates to an improved laparoscopic surgical instrument that can simultaneously perform multiple tasks and procedures independent of one another.
2. Discussion of Related Art
Laparoscopic surgery involves the use of small incisions to insert surgical instruments of 3-10 millimeter (mm) diameter into the abdominal cavity. In performing such surgery, telescopes of 5-11 mm diameter usually also are inserted through the abdominal wall in order to view intraabdominal contents during the surgery. The initial step in laparoscopic surgery is to insert a needle of about 2 mm diameter through the abdominal wall such that the tip of the needle lies in the abdominal cavity itself. About 2-4 liters of a medical grade sterilized gas such as carbon dioxide, is insufflated through the needle and into the cavity. This procedure separates the abdominal wall from the organs and also usually separates the organs from one another, as the case may be.
The traditional device for passage of an insufflating gas is the Verres needle which comprises an outer cannula which has a distal needle-like tip for puncturing the abdominal wall and an expanded opposite portion which houses a spring mechanism for retraction of an inner cannula or obturator. The obturator comprises a hollow tube having an enclosed, rounded distal end with a lateral port in close proximity to the said distal end. As the Verres needle penetrates the epidermis and abdominal wall, the obturator retracts into the outer cannula against the bias of the spring to facilitate penetration through the abdominal wall. After penetration of the abdominal wall, the distal end of the obturator is spring-biased out of the Verres needle into the abdominal cavity. An insufflating gas then is delivered to the abdominal cavity from a gas supply detachably connected to the Verres needle so that the insufflating gas can enter the expanded portion of the outer cannula and traverse inside the inner cannula and enter the abdominal cavity through the lateral port located in the distal end of the inner cannula. In this case, the obturator and insufflating gas share a common passage or channel within the inner cannula. The insufflating gas serves to separate the abdominal wall from underlying organs.
In some known devices, the obturator can be removed so that a medical instrument, such as an endoscope, can be inserted into the space vacated by the obturator and inserted into the abdominal cavity. One disadvantage of the inserting the medical instrument into the Verres needle is that the medical instrument causes a significant restriction to the flow of insulating gas within the Verres needle since the medical instrument and the insufflating gas share a common passage or channel in the inner cannula. Such restriction in flow of the insufflating gas can limit the effectiveness of the insufflator.
Known trocars are similar to the above-described Verres needle in that they have a cannula that forms a single passage that contains both the insufflating gas and an obturator. One difference between a trocar and a Verres needle is that the Verres needle is typically a 14 gage needle size while trocars are known to have sizes ranging from 10 to 12 mm. One similarity between a trocar and a Verres needle is that the trocars are known that allow the obturator to be removed so that a medical device, such as an endoscope, can be inserted into the cannula. Like the Verres needle described previously, inserting the medical instrument into the cannula causes a significant restriction to the flow of insufflating gas within the trocar due to the sharing of a common passage by the medical instrument and the insufflating gas.
Another disadvantage of insertion devices, such as Verres needles and trocars, is that only one fluid can be conveyed within the insertion device at any one time. If multiple fluids are needed to be conveyed to or from the abdominal cavity for instance, then multiple Verres needles or trocars would be needed where each Verres needle or trocar is associated with only one of the multiple fluids. Using multiple insertion devices lead to the disadvantages of increasing the cost of the procedure, the complexity of the procedure and potentially increasing trauma incurred by the patient.
In the alternative, a single Verres needle or trocar could be used where one of the multiple fluids would be conveyed at one period of time and the other multiple fluids would be conveyed at separate and distinct time. Such a mode of operation could lead to contamination of the Verres needle or trocar with multiple fluids, increase the complexity of timing the application of fluids and requiring special metering and/or control devices.